Radial expansion of tubular elements has been applied, for example, in wellbores whereby a tubular casing is lowered into the wellbore in unexpanded state through one or more previously installed casings. After the casing is set at the required depth, an expander is moved through the casing to radially expand the casing to an inner diameter which is about equal to the inner diameter of the previously installed casing(s). In this manner it is achieved that the inner diameters of subsequent casings are about equal as opposed to conventional casing schemes which have stepwise decreasing casing diameters in downward direction.
A problem of expanding such tubular elements is the large force required to move the expander through the tubular element. Furthermore, in case the expander is moved through the tubular by applying fluid pressure at the side of the large diameter part of the expander there is a danger of burst of the tubular element when the high fluid pressure exceeds the burst pressure of the tubular element.